Project GammaProject GammaBy Wylie Ballinger and Sam Russell

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What are Gamma Rays?What are Gamma Rays? The most potent particles The most potent particles

on the electromagnetic on the electromagnetic scale and the known scale and the known universe.universe.

‘ ‘1 1 TeVTeV (1,000,000,000,000 eV, (1,000,000,000,000 eV, where an optical photon where an optical photon has an energy of a few eV’ has an energy of a few eV’ http://imagine.gsfc.nasa.gov/docs/scihttp://imagine.gsfc.nasa.gov/docs/science/how_l2/gamma_detectors.htmlence/how_l2/gamma_detectors.html

Smallest wavelengthSmallest wavelength Quite rare.Quite rare. Only created by Only created by

radioactive atoms and radioactive atoms and nuclear reactions.nuclear reactions.

The hottest regions of the The hottest regions of the universe produce them.universe produce them.

Formed by Supernovae, Formed by Supernovae, Pulsars, Neutron Stars, Pulsars, Neutron Stars, Black holes, and Gamma Black holes, and Gamma Ray Bursters.Ray Bursters.

‘electron voltThe change of potential energy experienced by an electron moving from a place where the potential has a value of V to a place where it has a value of (V+1 volt). This is a convenient energy unit when dealing with the motions of electrons and ions in electric fields; the unit is also the one used to describe the energy of X-rays and gamma rays. A keV (or kiloelectron volt) is equal to 1000 electron volts. An MeV is equal to one million electron volts. A GeV is equal to one billion (109) electron volts. A TeV is equal to a million million (1012) electron volts.’ http://imagine.gsfc.nasa.gov/docs/science/how_l2/gamma_detectors.html

Seeing in GammaSeeing in Gamma Explorer XI launched first satellite in 1961 was Explorer XI launched first satellite in 1961 was

the first gamma ray receiver.the first gamma ray receiver. It picked up fewer than 100 cosmic gamma-ray It picked up fewer than 100 cosmic gamma-ray

photons total.photons total. CGRO satellite.CGRO satellite. The moon gives off more Gamma Rays than The moon gives off more Gamma Rays than

the sun.the sun. Mirrors don’t workMirrors don’t work

How Do We See Gamma?How Do We See Gamma?

1-30 MeV Is the ideal range that we wish to 1-30 MeV Is the ideal range that we wish to see.see. Active galaxies, pulsars, and solar flares.Active galaxies, pulsars, and solar flares.

Compton Scattering and how it works.Compton Scattering and how it works.

How Do We See in Gamma? Continued…How Do We See in Gamma? Continued…

I’m a visual person…

http://learntech.uwe.ac.uk/radiography/RScience/interactions/comptonscatter.htm

So How Does That Work So How Does That Work Again?Again?

Crystal Scintillators Crystal Scintillators Crystals that emit low energy light (usually visible) when hit by high energy light Crystals that emit low energy light (usually visible) when hit by high energy light

such as gamma radiation.such as gamma radiation. Pair ProductionPair Production

The physical process whereby a gamma-ray photon, usually through an The physical process whereby a gamma-ray photon, usually through an interaction with the interaction with the electromagneticelectromagnetic field of a nucleus, produces an electron and field of a nucleus, produces an electron and an anti-electron (an anti-electron (positronpositron). The original photon no longer exists, its energy having ). The original photon no longer exists, its energy having gone to the two resulting particles. The inverse process, pair annihilation, creates gone to the two resulting particles. The inverse process, pair annihilation, creates two gamma-ray photons from the mutual destruction of an electron/positron pair. two gamma-ray photons from the mutual destruction of an electron/positron pair. http://imagine.gsfc.nasa.gov/docs/dict_jp.html#pair_productionhttp://imagine.gsfc.nasa.gov/docs/dict_jp.html#pair_production

CGRO uses compton scattering and pair production.CGRO uses compton scattering and pair production. Launched in April 5th, 1991 on Atlantis shuttle. Had a visual range of 30 KeV to Launched in April 5th, 1991 on Atlantis shuttle. Had a visual range of 30 KeV to

30 GeV30 GeV Burst And Transient Source Experiment (Burst And Transient Source Experiment (BATSEBATSE), the Oriented Scintillation ), the Oriented Scintillation

Spectrometer Experiment (Spectrometer Experiment (OSSEOSSE), the Imaging Compton Telescope ), the Imaging Compton Telescope ((COMPTELCOMPTEL), and the Energetic Gamma Ray Experiment Telescope (), and the Energetic Gamma Ray Experiment Telescope (EGRETEGRET). ). http://http://cossc.gsfc.nasa.govcossc.gsfc.nasa.gov//

Returned to Earth on June 4th 2000.Returned to Earth on June 4th 2000. Gamma-ray Large Area Space Telescope is being sent up by Nasa in 2007.Gamma-ray Large Area Space Telescope is being sent up by Nasa in 2007.

Gamma Ray BurstersGamma Ray Bursters Does what it says on the box.Does what it says on the box. http://imagers.gsfc.nasa.gov/ems/gahttp://imagers.gsfc.nasa.gov/ems/ga

mma.htmlmma.html

The most energetic things in the The most energetic things in the universe that we know of.universe that we know of.

More energy in 10 seconds than our More energy in 10 seconds than our sun can produce in its entire liftime sun can produce in its entire liftime of 10,000,000,000 years!of 10,000,000,000 years!

GLASTGLAST

Gamma-Ray Large Area Gamma-Ray Large Area Space Telescope Large Area Space Telescope Large Area TelescopeTelescope

Funded Jointly by the US, Funded Jointly by the US, Japan, France and SwedenJapan, France and Sweden

Accuracy of 30 Arc secondsAccuracy of 30 Arc seconds

Launch in 2006Launch in 2006

CGROCGRO

Compton Gamma Ray ObservatoryCompton Gamma Ray Observatory

Four telescopes on it:Four telescopes on it:1. BATSE1. BATSE

Base and Transient Source ExperimentBase and Transient Source Experiment

2. OSSE2. OSSE Oriented Scintilliation Spectrometer ExperimentOriented Scintilliation Spectrometer Experiment

3. COMPTEL3. COMPTEL Imaging Compton TelescopeImaging Compton Telescope

4. EGRET4. EGRET Energetic Gamma Ray Experiment TelescopeEnergetic Gamma Ray Experiment Telescope

CGRO EGRETCGRO EGRET

The Compton Gamma The Compton Gamma Ray Observatory Ray Observatory Energetic Gamma Ray Energetic Gamma Ray Experiment TelescopeExperiment Telescope

8080° Field of View° Field of View

Launched in 1991 as an Launched in 1991 as an Experimental ProgramExperimental Program

Re-entered in 2004Re-entered in 2004

Major EGRET DiscoveriesMajor EGRET Discoveries The finding of a new class of objects--high The finding of a new class of objects--high

energy gamma-ray emitting blazars, or grazars energy gamma-ray emitting blazars, or grazars The emission of high energy gamma-rays from a The emission of high energy gamma-rays from a

gamma ray burst for over an hour, with some gamma ray burst for over an hour, with some gamma rays having energies over a GeV and gamma rays having energies over a GeV and two having energies over 10 GeV. two having energies over 10 GeV.

The observation of an increased fraction of The observation of an increased fraction of pulsar electromagnetic radiation going into pulsar electromagnetic radiation going into gamma rays as the age of the pulsar increases to gamma rays as the age of the pulsar increases to a million years a million years

The determination with high certainty that The determination with high certainty that cosmic rays are galactic cosmic rays are galactic

The detailed mapping of the galactic diffuse The detailed mapping of the galactic diffuse radiation and the measurement of the pion bump radiation and the measurement of the pion bump in the high energy gamma-ray spectrum in the high energy gamma-ray spectrum

The absence of microsecond bursts and its The absence of microsecond bursts and its implication for certain unification theories implication for certain unification theories

The long trapping time of over ten hours for The long trapping time of over ten hours for energetic solar particles following a flare energetic solar particles following a flare

A measurement of the diffuse, presumably A measurement of the diffuse, presumably extragalactic, high energy gamma ray spectrumextragalactic, high energy gamma ray spectrum

http://lheawww.gsfc.nasa.gov/docs/gamcosray/EGRET/http://lheawww.gsfc.nasa.gov/docs/gamcosray/EGRET/highlights.html highlights.html

INTERGRALINTERGRAL International Gamma-Ray International Gamma-Ray

Astrophysics LaboratoryAstrophysics Laboratory

European Space Agency European Space Agency Demark, France, Germany, Italy, Demark, France, Germany, Italy,

Spain and SwitzerlandSpain and Switzerland + Czech Republic and Poland+ Czech Republic and Poland With help from Russia and USWith help from Russia and US

Giant molecular Giant molecular cloud in the center of cloud in the center of the galaxy that was the galaxy that was just recently just recently discovereddiscovered

Gamma-Ray Burst over 40 SecondsGamma-Ray Burst over 40 Seconds

http://www.rssd.esa.int/Integral/integ_images.html

A Cool Picture !!!A Cool Picture !!!

SourcesSources http://http://imagers.gsfc.nasa.gov/ems/gamma.htmlimagers.gsfc.nasa.gov/ems/gamma.html http://science.nasa.gov/newhome/headlines/ast09feb99_1.htmhttp://science.nasa.gov/newhome/headlines/ast09feb99_1.htm http://http://www.wordiq.com/definition/Gamma_ray_burstwww.wordiq.com/definition/Gamma_ray_burst http://imagine.gsfc.nasa.gov/docs/science/how_l2/compton_scatter.hthttp://imagine.gsfc.nasa.gov/docs/science/how_l2/compton_scatter.ht

mlml

http://imagine.gsfc.nasa.gov/docs/science/how_l2/gamma_detectors.hthttp://imagine.gsfc.nasa.gov/docs/science/how_l2/gamma_detectors.htmlml

http://imagine.gsfc.nasa.gov/docs/science/how_l1/gamma_detectors.hthttp://imagine.gsfc.nasa.gov/docs/science/how_l1/gamma_detectors.htmlml

http://www.astro.utu.fi/~cflynn/astroII/l7.htmlhttp://www.astro.utu.fi/~cflynn/astroII/l7.html http://learntech.uwe.ac.uk/radiography/RScience/interactions/comptonhttp://learntech.uwe.ac.uk/radiography/RScience/interactions/compton

scatter.htmscatter.htm

http://imagine.gsfc.nasa.gov/docs/science/how_l2/http://imagine.gsfc.nasa.gov/docs/science/how_l2/gamma_scintillators.htmlgamma_scintillators.html